Piston Mods and Machining
02-06-2004, 04:29 PM
#48
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How much did it cost per piston?
If i were to take a batch down now im sure there would be another set up fee...I just just did 16...I got a great deal i think, so did the other guy who had them done.
I had already done much of the set up my self with the original piston. All the dimensions for the S4 piston and the dish i created are now stored in a CAD program and can be altered VERY easily. Point ...click..drag..push the button, shavings fly and the computer turns it.
Oh..let say less than 50 bucks would have you well covered.
The test will be to see how they work and how they last in this "structural" state
rder: LMAO.....we have new "smiles" to pick from!
I like this one!!
02-06-2004, 04:55 PM
#49
Three Wheelin'
Originally posted by Tony
Oh..let say less than 50 bucks would have you well covered.
Oh..let say less than 50 bucks would have you well covered.
The 'order' icon does not work because another one has the same first two characters.
03-19-2004, 09:20 PM
#50
I think I have to verfiy this, but it looks like this process ( a great one it is) can only be done with 87 pistons or maybe earlier. My 89 pistons, which I had just planned on sending out to get done, are thinner, by my visual, then these of tony's.
So now I have to come up with another solution.
So now I have to come up with another solution.
03-19-2004, 09:39 PM
#51
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Build the MONSTER!
LOL!
Actually, if you want to just run the supercharger on your regular pistons, it should be fine, and plenty fast, and you can still just keep working on your other project...
LOL!
Actually, if you want to just run the supercharger on your regular pistons, it should be fine, and plenty fast, and you can still just keep working on your other project...
03-19-2004, 10:17 PM
#52
The monster will be built. And If it all works out, I was thinking about a 106mm bore with the stroker crank from one the people who do them. That would be a 6.6L. Then add boost.
Butthe key here is WHILE I am driving this car.
Butthe key here is WHILE I am driving this car.
03-19-2004, 10:57 PM
#53
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Makes sense...
I think that would make sense to most people planning to build a stroker, or other motor. If all you are doing, is bolting a supercharger to your engine, then it can stay in the car, and you are only down a weekend or two. But if you are planning a *big* engine build, which could take months, or even over a year (Sterling), then it would make a lot of sense to buy a second block, and do all the work on the new engine, while the car stays on the road, until the day comes for the finished engine to be installed...
I think that would make sense to most people planning to build a stroker, or other motor. If all you are doing, is bolting a supercharger to your engine, then it can stay in the car, and you are only down a weekend or two. But if you are planning a *big* engine build, which could take months, or even over a year (Sterling), then it would make a lot of sense to buy a second block, and do all the work on the new engine, while the car stays on the road, until the day comes for the finished engine to be installed...
07-29-2004, 07:49 PM
#54
Developer
I've been reading this thread with interest. Good stuff.
I'm about to build up a new motor for my track car - it will be supercharged (of course) and it will be CIS on top. I'm at the penciling around stage - and came to some of the same conclusions as you did Tony - if I could get r done with stock Pistons and rods I'd not have Alusil compatability problems and a lower finished cost.
But... you do not have to bore a 5.0 block very far to get it to accept Chevy forged pistons, do you? Does anybody know - done this? The forged pistons are readilly available in certain sizes (Chevy/Ford) and cheap - can we adapt to fit? ...and get low cost and the strength of forged pistions?
I'm about to build up a new motor for my track car - it will be supercharged (of course) and it will be CIS on top. I'm at the penciling around stage - and came to some of the same conclusions as you did Tony - if I could get r done with stock Pistons and rods I'd not have Alusil compatability problems and a lower finished cost.
But... you do not have to bore a 5.0 block very far to get it to accept Chevy forged pistons, do you? Does anybody know - done this? The forged pistons are readilly available in certain sizes (Chevy/Ford) and cheap - can we adapt to fit? ...and get low cost and the strength of forged pistions?
04-07-2007, 07:49 PM
#55
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Digging old thread back up as I think its good know to below info in case someone is thinking about doing what Tony did. Didn't read entire thread if this has been mentioned before though.
Factory documents say S4 pistons were changed in February '88. Officially only change was strenghtening of skirts and addition of oil drain holes on skirts below pin ends. It seems February '88 or year later done GT piston indroduction was larger change than that. I do not know which of these dates change was done as two pistons I compared today were from '87 and '90 S4. So its possible change in S4 pistons was done at beginning of '90 MY when high compression GT pistons were taken into use in S4 also.
In any case, change was totally different piston casting. Early and late S4 pistons are not same. Both were done by Kolbenschmidt. Tony's pictures and measurements are for old style. On new style piston apart from dish being smaller also material thickness at center of the dish is about 1mm thinner than in early style. It makes sense since piston weight is same and late style pistons do have thicker skirts at 12 and 6 o'clock looking from the side of the engine. Without removing material from somewhere else they would weight more than early style. Thinning seem to have been done only at center of the piston. Besides different casting also oil holes behind oil ring received rounding on inside same way as drain holes on skirt are rounded at both ends.
This is just heads up in case someone is thinking about taking material away from dish like Tony did. End result is going to be approximately 1mm thinner than Tony's measurement
Factory documents say S4 pistons were changed in February '88. Officially only change was strenghtening of skirts and addition of oil drain holes on skirts below pin ends. It seems February '88 or year later done GT piston indroduction was larger change than that. I do not know which of these dates change was done as two pistons I compared today were from '87 and '90 S4. So its possible change in S4 pistons was done at beginning of '90 MY when high compression GT pistons were taken into use in S4 also.
In any case, change was totally different piston casting. Early and late S4 pistons are not same. Both were done by Kolbenschmidt. Tony's pictures and measurements are for old style. On new style piston apart from dish being smaller also material thickness at center of the dish is about 1mm thinner than in early style. It makes sense since piston weight is same and late style pistons do have thicker skirts at 12 and 6 o'clock looking from the side of the engine. Without removing material from somewhere else they would weight more than early style. Thinning seem to have been done only at center of the piston. Besides different casting also oil holes behind oil ring received rounding on inside same way as drain holes on skirt are rounded at both ends.
This is just heads up in case someone is thinking about taking material away from dish like Tony did. End result is going to be approximately 1mm thinner than Tony's measurement
04-07-2007, 09:47 PM
#56
I found this out when I wanted to do Tony's process to my 89 S4 pistons. They seemed quite a bit thinner then what it measured in the pics.
I did not know more material, however, was added to the pin area - is that what you are saying?
I did not know more material, however, was added to the pin area - is that what you are saying?
04-07-2007, 09:56 PM
#57
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Originally Posted by BrendanC
I did not know more material, however, was added to the pin area - is that what you are saying?
04-07-2007, 11:46 PM
#58
Oh. I wonder why. Of course - I did take out a piston that was cracked there - but I think I did that.
04-08-2007, 08:02 AM
#59
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I agree with T_Max
The most cost effective solution is to get a thicker headgasket (watercut steel or copper)
And _maybe_ ceramic coating on stock S4 heads, or/and better fuel cooling (zub zero).
Local 928 turbo with thicker headgaskets:
http://www.thorupauto.dk/projekt-928.htm
The most cost effective solution is to get a thicker headgasket (watercut steel or copper)
And _maybe_ ceramic coating on stock S4 heads, or/and better fuel cooling (zub zero).
Local 928 turbo with thicker headgaskets:
http://www.thorupauto.dk/projekt-928.htm
04-12-2007, 08:40 PM
#60
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not trying to undermine your effort - it's pretty cool for sure. but every engine builder on the planet recommends forged over cast pistons for SC or HP use cause the forged stuff is stronger and runs cooler/less detonation issues, lighter, bla bla bla...
so I guess I'd have to ask, why all this for old cast pistons? you spent 50x8 =400 bones for "timebombs" and for only $600 more you could have custom forged JE's or whatevers.
well, ok plus some nicom work for $900 or so. but since to reprep the cyls it's around $800 anyway, nicom is only about $100 more at the end of the day and you get a much better setup. and beats trashing everything when it grenades/destroying the block/god knows what else, doing it all over again, and gives better lubrication/wear too.
just asking....
so I guess I'd have to ask, why all this for old cast pistons? you spent 50x8 =400 bones for "timebombs" and for only $600 more you could have custom forged JE's or whatevers.
well, ok plus some nicom work for $900 or so. but since to reprep the cyls it's around $800 anyway, nicom is only about $100 more at the end of the day and you get a much better setup. and beats trashing everything when it grenades/destroying the block/god knows what else, doing it all over again, and gives better lubrication/wear too.
just asking....